Limestone itself is quarried in lots of places like a setting up stone, for use in roads, and for use in decreasing sulfur emissions from coal-burning electric power crops. Phosphates happen to be mined for fertilizer from Ordovician limestones, notably wherever weathering has concentrated the phosphate, as in central Tennessee. https://trichostatin-a32457.rimmablog.com/27978624/the-smart-trick-of-eupatilin-that-nobody-is-discussing